1. Field
This application relates generally to mesh networks, and more particularly to saving power while delivering traffic in mesh networks.
2. Background
802.11 is a set of IEEE standards that govern wireless networking transmission methods. Several versions of 802.11 are used to provide wireless connectivity in the home, office and some commercial establishments. IEEE standards include versions 802.11a, 802.11b, 802.11g, etc. IEEE 802.11s is a draft IEEE 802.11 amendment for mesh networking. Mesh networking defines how wireless devices interconnect, creating an extended ad-hoc network in which multiple hops may need to be traversed.
Currently in mesh networking, mesh nodes can be allowed to enter a power saving mode while remaining in contact with their peer mesh nodes. Power saving mesh nodes start an Awake Window after each beacon they transmit. Traffic buffered for a peer mesh node in power save is indicated through a mesh traffic indication message (TIM) field in the beacon. When a power saving mesh node sees its TIM bit set in a received beacon, it starts a service period during the peer station's (STA) Awake Window (if it is asleep also). The buffered traffic is then delivered during this service period.
One problem with the current power saving method is that the power saving mesh node needs to receive beacons from all of its peers, which given the duration of the beacon and the frequency of its transmission can result in quite a lot of wake time, while most of the time the TIM bits will not be set anyway. Accordingly, it would be desirable to have a power saving method which would allow data transmission without requiring nodes to receive and examine beacons from all peer nodes.